Yet, salivating and open mouthed, we wait hungrily for our next burger.

Meat production has skyrocketed over the past half-century. In 1950, around 55 million tons of meat were produced globally. But just five years ago, that number was more than 300 million. And global demands for meat are on the rise. But experts argue the effects and by-products of the global meat industry are catching up with consumers and are already taking a toll on our planet.

How much longer can we sustain the current trend?

Probably not long.

This week, Mother Jones drew attention to a 2014 paper by an ecologist named Vaclav Smil in which he examines the industry's sustainability at its current levels. Smil found that, perhaps unsurprisingly, we simply can't afford to keep cramming animals into overcrowded pens and stuffing them with corn and soybeans –– what's called the feedlot system –– especially with countries like China taking cues from our deeply efficient, destructive system.

Smil says that as meat production has shot up in recent decades, so has its costs to our environment. The long shift to industrial-scale feedlot meat has given rise to many iterations of harmful, less diversified categories: a shift away from heterogeneous farmland and rainforests, reliance on a few select animal breeds, and monocultures of engineered feed crops, which Mother Jones notes has triggered soil erosion, carbon emissions, and coastal "dead zones" created by fertilizer runoff. Moreover, volumes of animal waste produced by too-dense concentrations of animals are often too massive to effectively be fertilized into nearby farmland, and end up seeping into water and air supplies.

But Smil argues that because global meat demands continue to rise, the systems needed to produce enough product –– the American feedlot model –– would ultimately undermine the very ecosystems that feed it. By Smil's calculations, at current levels of increasing demand, the globe would need 412 million tons of meat by 2030, 500 million by 2050, and 577 million by 2080. At that point, the taxes of the system would be unsustainable –– they already are.

So what's the answer, then?

Well, essentially, get used to eating less of it.

Like any paleo diet prosthelyte will tell you, meat has been an essential factor in human evolution––and it's not likely going anywhere fast. But as Smil argues in the paper, we're no longer eating it for nutrition, instead categorizing it as a bountiful, (cheaper) luxury. Only half of the meat an average American consumes per year is "compatible with good health and high longevity," he writes. Eating less could be in step with systemic reforms to industrial meat production, too. By ditching monoculture feed crops like corn and soybeans, not only would the animals be healthier (and likely taste better), but they would be able to work more harmoniously with their surroundings. Smil says that animals could be dispatched on to pastures in rotation with crops, sustaining themselves solely on seasonal crop residuals and food waste, and producing about 200 million tons of meat per year––enough to feed global populations healthy amounts of meat.

What are they blocks to moving to a system like this?

The blocks are relatively few, but monolithic. Big agribusiness companies are notoriously some of the most powerful, when it comes to challenging monopolies they hold on things like a particular strain of corn or soy used for feed. It's estimated that Monsanto, one of the largest agribusinesses, makes over 90 percent of soybeans sold in the U.S., and 80 percent of the corn. And they lobby heavily to protect their patents on those products: last year, the company spent over $4.1 million in agricultural services and products lobbying, and more than $1.2 million this year alone. Moreover, if populations in meat-heavy countries began scaling back to more than half their normal consumption levels, international meat-production companies like Tyson, JBS, and Smithfield would be unlikely to stand idly by.

Mother Jones points out that since 2009, when the total annual slaughter in the U.S. peaked at 9.5 billion animals, annual slaughter numbers have edged off a bit. Whatever the reason for that being, we'll be needing more of it in the coming years.